Light emitting diode (LED) illumination systems have been developed to replace the conventional incandescent—or fluorescent—based systems to reduce energy costs and increase reliability. LED illumination systems consume less energy than systems containing conventional sources while exhibiting much longer lifetimes. Such systems are typically made by mounting a plurality of LEDs to a flat printed circuit board (PCB), with the flat surface of the PCB on which the LEDs are mounted facing toward the desired direction of the light output.
LED illumination systems are versatile and have been used across a broad range of applications. For example, optical systems utilizing LEDs can have applications in area lighting, flashlights, spot lighting, customizable/adjustable lighting systems, household lighting, wearable headlamps or other body-mounted lighting, among others. Optical systems also find application in area lighting, for example in streetlights or otherwise. Area lighting presents unique requirements for illumination coverage and uniformity, e.g., on a roadway or pathway, with a minimum number of lighting fixtures. The use of optical systems, whether for area lighting or otherwise, for such a range of applications subjects them to a variety of environments.
Accordingly, an object of the invention is to provide improved devices and methods for area lighting. A further object of the present invention is to provide an optical system for use in various environments, both indoor and outdoor, whether wet or dry, while protecting the optical system from fouling.